"I don't think we're going beyond our remit in supporting Action Earth. The more we can get people and business thinking about the environment, the less we shall have to come in afterwards and shut the stable door after the horse has bolted.

"And if we get someone wanting to do a project tackling climate change, say, where some people insist there isn't a problem, I think that's a proper use of the agency's money and time."

She said if people waited until there was "absolutely indubitable proof" of climate change "it'll be too late for all of us".

"We can't just sit there frozen in the headlights for 20 years until it's completely certain."